INSTINCT IN INSECTS. l$l 



tends to become general, since it is advantageous, and we thus fall 

 back into a particular case of the great principle of natural selection 

 formulated by Darwin. Let us go on. Thus far this instinct is but 

 little complicated, since it has only the significance of a habit that one 

 individual may have been able to take up with its share of intelli- 

 gence. Now that it is seen rooted under the form of instinct, each in- 

 dividual in its turn, with its own share of intelligence, may be able to 

 add something to it of its own accord. If that addition is still favor- 

 able, and again gets transmitted, it will tend in the same way to be- 

 come general ; the acquired instinct will grow so much the more com- 

 plex ; and, exactly as organic modifications scarcely perceptible, but 

 accumulated successively, to a sufficient number, have been able to 

 multiply animal forms infinitely, so instinct, by almost imperceptible 

 but continuous additions, may be able to end by reaching that state of 

 perfection in which philosophers had supposed they saw the convincing 

 proof of a preestablished harmony. 



Some naturalists even now are not, very fortunately, inspired when 

 they attempt to prove to us that the corporeal organization of every 

 animal is conceived and framed with regard to its instincts. We need 

 not go far to learn, as indeed we might expect from what has gone be- 

 fore, that instinct is in many cases independent of external forms. All 

 birds, whether they are masons, like the swallow ; weavers, like the 

 warbler; carpenters, like the crow ; mound-builders, like the megapode 

 have the same beak, the same claws, and forms almost the same. 

 The European beaver, inhabiting the affluents of the Rhone and the 

 Danube, is scarcely to be distinguished from the American beaver, yet 

 he has quite a different kind of work to do. The American beaver, 

 on his lakes and great, lonely rivers, builds the famous houses so well 

 known ; the European beaver burrows long galleries underground in 

 the manner of moles. If he has always done so, what becomes of that 

 supposed necessary correlation between the organs and the instinct of 

 a burrowing animal on one continent, a building animal on the other, 

 with the same members for two objects so different ? If the European 

 beaver did once build huts, where shall we find more decisive testimony 

 in favor of the theory of mutability in instincts ? Pursued for his 

 warm covering and his flesh, he has changed his instincts, before in- 

 vading civilization, more rapidly than his external form. It is a point 

 well established at this day that the contact with man has had a deci- 

 sive effect on the instinct of many animals. It is thus that in inhabited 

 countries large birds take flight at his approach, while they still allow 

 him to come close to them in countries visited by travellers for the 

 first time. Wherever they have been hunted like a prey that is worth 

 the trouble of pursuit for their flesh or their feathers, they have formed 

 the habit, and then have had the instinct of taking flight. 



Let us return to insects. Two instincts, the most remarkable among 

 all, are presented by them ; that of the bee, with its mathematical 



